Low voltage switchgear assemblies are commonly used in electric power distribution systems such as those typically used to provide power to factories, buildings and commercial installations. Such assemblies are mounted in metal cabinets and include combinations of electrical apparatus for the power distribution systems. Such apparatus typically includes circuit breakers or other switching devices and switching disconnect switches to separate or isolate individual parts of the distribution system. Network protectors may also be included as well as transfer switches used for connection of the system to alternate power sources. Metering equipment and other instrumentation may also be provided.
A continuing need has existed for improved bus bar configurations that take advantage of the “skin” effect of such conductors to reduce the amount of copper required to conduct a given amount of electrical current. The skin effect is a descriptive term for the phenomenon that the bulk of electrical current flows in the outer perimeter or surface of a conductor. Thus, the material at the interior of a conductor, while just as costly to produce, is significantly less efficient in use as a conductor than the material at the perimeter. Most bus bars used in low voltage switchgear have, heretofore, been formed from flat copper bars because of ease of manufacture and assembly. It is desirable to minimize the cost of the bus bar assemblies by reducing the amount of copper contained therein.
One obstacle that has existed and has prevented the development of the most efficient bus bar configurations and geometrics has been the difficulty in connecting hollow vertical conductors with high efficiency horizontal bus bars.